Armor-piercing projectile



R. A. HADHELD AND-A. G. MCK'. IACK. ARMOR PIERCING PROJECTILE.APPLICATION FIL 6.17. I9|8 Patented Nov. 29,- 1921.

ROBERT ABBOTT HADFIELD, OF WESTMINSTER, AND ALEXANDER GEORGE IVICKENZIEJACK, 0F SI-IEFFIELD, ENGLAND.

ARMORf-PIERCING- PROJECTILE.

Application led December 17, 1918.

T0 all whom t may concern.'

Be it known that we, ROBERT ABBOTT I-IAD- FIELD' and ALEXANDER GEORGEMOKENZTE JACK, subjects of the King of Great Britain and Ireland,residing, respectively, at the city of Westminster, England, andSheffield, in the county of York, England, have invented Improvements inor Relating to Armor-Piercing Projectiles, of which the following is aspecification.

Heretofore armor piercing projectiles have been made with their ogivalpointed heads in one piece of metal and integral with the bodies of theprojectiles. When such a projectile strikes a hard faced armor plate,particularly when striking Vobliquely, there is a liability of theforward portion of its head being broken off or of a fracture being setup therein that will probably extend backward to the chamber or core ofthe projectile, with the result that although the projectile mayperforate the plate, it is prevented from properly performing itsrequired function of effective 'detonation Now this invention has forits obj ect so to construct an armor piercing projectile as to preventany fracture that may occur in the forward portion of the head of such aprojectile extending backward to the rearward portion thereof and thenceto the detonating charge of the projectile, so that the projectile shallbe better adapted than heretofore to successfully perforate a hard facearmor plate and perform its proper function, even when striking theplate obliquely at a large angle. Y

For this purpose, the ogival pointed head of an armor piercingprojectile is made in separate parts arranged one in front of the other,the rear or rearmost part being formed in one with the body of theprojectile. Conveniently, the head may he made in two parts fitting oneVinto the other and held together in any suitable way, it may be by theforward portion being inclosed in the metal cap with which theprojectile is fitted for use and which is preferably secured in place byforcing portions of its rear end into notches, formed in the shoulderportion of the projectile in a known way. Means may be provided forvpreventing the forward portion of the head turningon the rearportionthereof or projectile proper against which it bears. For this purposetwo or more small dowel pins may be used arranged Specification ofLetters Patent.

Serial No. 267,202.

to extend into each of the adjacent parts of the head. The forwardpointed portion of the head of the projectile may be of ogival shape ofany desired radius. The forward end of the projectile proper,constituting the rear part of the head, which is inclosed within the capand retains in position the forward portion of the head, when the headis formed of two portions only, is of pointed form and may be ofconical, or other shape and such as to form a blunt true head to theprojectile ofsuch a shape that it will serve to prevent the forwardportion, which rests upon it, being displaced laterally on impactagainst an armor plate, even at a considerable angle. The dividingsurface between the two parts should terminate circumferentially in aline intermediate of the length of the ogival or equivalent shapedsurface of the divided head and forward of the points of connectionbetween the projectile and the cap fitted over the head. The axialthickness of the forward part of the head may be varied to suitrequirement, but in the case where the head is made as described, goodresults have been obtained with an Patented Nov. 29, 1921.

axial thickness equal approximately to 40 to 50% of the caliber of theprojectile.

The accompanying drawing shows partly in central longitudinal sectionand partly in side elevation and byway Of example only, an armorpiercing projectile having its head made in two parts according to theinvention and provided with a cap and with a hollow point or airdeflector.

In this example, the head of the projectile is made in two parts a andal fitting one into the other, the separate forward part al being ofogival shape and the rear part a, which is in one piece with the body oof the projectile, and has a central forward end portion of conicalshape closely fitting into a similar shaped recess in the rear side ofthe forward portion, c, c1 being the line of division between the twoparts. The circumferential surface of the rear part a of the head of theprojectile is of ogival shape flush with and forming a continuation ofthe ogiy place by forcing portions Z1 of its rear end into notches orrecesses a2 in the shoulder portion of the projectile to the rear of theline of division c, c1 between the two parts a, al of the head of theprojectile. e is a hollow point or air deflector of an ordinary kindsecured over the forward end portion of the cap cl .and flush with theouter' surface thereof as usual. Means, such as dowel pins f may befitted to the two parts of the head to prevent relative turning movementbetween such parts.

The separate forward part al and also the rear part a of the head of theprojectile, as well as the cap cl that is fitted over the divided headof the projectile, are hardened and tempered. The hardening andtempering of the cap l in front of the head is or may be such that onimpact of the cap against the hard faced armor plate it will partiallybreak up the hard face of the plate and effect disintegration thereof ofsuch a nature that the separate forward part al of the head of theprojectile will complete the breaking up of t-he face to such a furtherextent that the rear part a of the head, that is of the projectileproper, will complete the perforation without fracture thereofoccurring, even if the projectile strikes the plate at a large angle. Tothis end, the forward part al of the head may be hardened in such a waythat it is composed wholly, or nearly so, of successive zones of steelof A and B ball hardness while the rear part kof the head is composed ofsuccessive zones of steel of A, B, C, D and E ball hardness, it beingunderstood that A ball hardness corresponds to a hardness of 600 andabove on the Brinell scale; B ball hardness to a hardness correspondingto 500 to 600; C ball hardness to a hardness corresponding to 300 to 400and E ball hardness corresponding to a hardness of 300 and below. Thevolumes of steel of A and B ball hardness in the rear portion a of thehead of the projectile may be small compared to the volumes of steel ofsimilar hardness in the separate forward portion a1 of the head. Thevolumes of steel of C and D ball hardness in the rear part of the head,that is of the projectile proper, may also be comparatively smallwhilethe volume of steel of E ball hardness, which extends to the base orrear end of the projectile, will be large.

The projectile with its separate forward portion may advantageously bemade of nickel chromium steel and of the composition set forth in thespecification of a former application for Letters Patent filed October4th, 1918. Serial No. 256,890. Also, the true head a and body of theprojectile may be hardened' and tempered in the manner described in thatspecification so that the successive zones of steel of decreasing ballhardness are in the form of shallow or flattened cups arranged onebehind the other and eX- tending more or less transversely. The sepa- Asan example, it may be stated that. an armor piercing projectile madewith a twopart head as described and suitably capped, the volume ofsteel of A and B ball hardness in the forward part of the head being inthe proportions respectively of about 85 and 65 and the volumes of steelof A, B, C, D and E ball hardness, in the rear or true head and body ofthe projectile being respectively in the pro ortions of about 12, 7, 3,4 and 74, successful y perforated a hard faced armor plate when strikingat an angle of 30G.

By graduating the hardness of the separate forward and rearward portionsof the divided head of the projectile in the manner described, eachportion is adapted to perforate an armor plate so that if under veryspecial conditions of attack, the forward portion of the'head shouldbecome broken off, the rear portion is nevertheless still available andcapable of continuing the perforating action. In this way, a projectilehaving a divided head, made as described, iskbetter adapted tosuccessfully perforate a hard faced armor plate and perform its properfunction than a projectile having an undivided head made as heretofore,even when -striking the plate obliquely at a large angle.

It will be understood that an armor piercing projectile having a dividedhead constructed as described is designed to fulfil a different functionto that of the cap with which it is fitted forruse, namely, to perforateand pass completely through a hard` faced armor plate, while the cap isdesigned to support the point of the projectile and break up the surfaceof the plate and then to itself become broken up to permit of the onwardmovement of the projectile in an intact condition through the preparedplate. Such a cap may thereforerbe said to be a frangible device,whereas thev divided head of theproj ectile is not.

What we claim is 1. An armor piercing projectile having a pointed ogivalshaped head made in separate parts fitted together one in front ofanother, the rear part being formed in one piece with the body of theprojectile and having its peripheral surface of ogival shape flush withand forming a continuation of the ogival surface of the remaining frontportion of the head of the projectile. Y

2. An armor piercing projectile having a pointed ogival shaped head madein two parts arranged one 1n front of the other, the

iso

rear part being formed integral with the body of the projectile andhaving a pointed front end portion litting a correspondingly shapedcavity in the rear end of the front part and a peripheral surface ofogival shape flush with and forming a continuation of theogival surfaceof Jdie front part of the head. v

3. An armor piercing projectile having a pointed ogival shaped head madein separate parts tted together one in front of the other, the rear partbeing integral with the body of the projectile and having its peripheralsurface of ogival shape flush with and forming a continuation of theogival surface of the remaining front portion or head of the projectileand means located between the engaging parts of the divided head of theprojectile to prevent relative turning movement between them.

4. An armor piercing projectile having a pointed ogival shaped head madein two parts, the rear part being integral with the body of theprojectile and having a pointed front end portion fitting into acorrespondingly shaped cavity in the rear end portion of the front partof the divided head and a peripheral surface of ogival shape flush withand forming a continuation of the ogival surface of the front part ofthe head, the axial thickness of the front part of the -head being ofthe order of about 40 to 50% of the caliber of the projectile.

5. An armor piercing projectile according to claim 2 made of hardenedand tempered steel, the front part of the divided head being composed ofsuccessive zones of steel of A and B ball hardness and the rear part ofsaid head bein composed of successive Zones of steel of A, 5B, C, D andE ball hardness.

6. An armor piercing projectile according to claim 2, made of hardenedand tempered steel, the frontpart of the divided head being composed ofsuccessive zones of steel of A and B ball hardness in the proportions,by volume of the order of about 35 and 65.

7 An armor piercing projectile according to claim 2, made of hardenedand tempered steel, the front part of the divided head being composed ofsuccessive zones of steel of of A and B ball hardness and the rear partof said head being composed of successive Zones of steel A, B, C, D andE ball hardness, the volumes of the successive zones of steel of A and Bball hardness in the rear part of the divided head of the projectilebeing small compared to the volumes of ythe successive zones of steel ofA and B ball hardness in the front part of the head so that theremaining portion of the rear part of the head is of greater toughnessthan the other portions.

8. An armor piercing projectile according to claim 2 made of hardenedand tempered steel, the front part of the divided head being composed ofsuccessive zones of steel of A and B ball hardness in the proportions,by volume, respectively of the order of about 35 and 65% and the rearpart of the divided head and body of the projectile being composed ofsuccessive zones of steel of A, B, C, D and E ball hardness in theproportions, by volume, respectively of about 12, 7, 3, 4 and 74%.

9. An armor piercing projectile having a pointed ogival shaped head madein separate parts fitted together one in front of another, the rear partbeing formed in one piece with the body of the projectile and having itsperipheral surface of ogival shape flush with and forming a continuationof the ogival surface of the remaining front portion of the head of theprojectile, and a cap of hardened and tempered steel fitting over thedivided head of the projectile and firmly Y engaged with the rear endpart of the divided head of the projectile.

10. An armor piercing projectile having an ogival shaped head made inseparate parts fitting one into the other and substantially flush witheach other externally with the rear part in one piece with the body ofthe projectile, the forward end of the rear part being of obtuseconoidal shape and suoli as to prevent the forward portion, which restsupon it, from being-displaced laterally on impact against an armorplate.

Signed at London, England, this eighteenth day of November 1918.

REERT ABBOTT HADFELD. ALEXANDER GEORGE McKENZlE JACK.

